Technician exam question T0A11
Subelement T0, SAFETY· Group T0A
What hazard exists in a power supply immediately after turning it off?
- A.Circulating currents in the dc filter
- B.Leakage flux in the power transformer
- C.Voltage transients from kickback diodes
- D.Charge stored in filter capacitors (correct answer)
WhyCharge stored in filter capacitors is a hazard in a power supply immediately after turning it off. Filter capacitors in a power supply can hold a dangerous stored charge for some time after the supply is switched off, since there's nothing left to discharge them once the AC input is removed, answer D. Circulating currents in a DC filter (A), transformer leakage flux (B), and kickback-diode transients (C) are all things that stop the moment power is removed, unlike a charged capacitor, which keeps its stored energy until it's deliberately discharged or bleeds off on its own.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2026-2030 NCVEC Element 2 pool (public domain); the explanation above is original writing, see our methodology.
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